An important problem in epilepsy is the evaluation of the clinical effectiveness of anticonvulsant drugs and the comparison of their effects on the mechanisms underlying the establishment of epileptogenic foci. Changes in local neuronal oxidative metabolism will be measured in animals during the progressive initation and establishment of primary and secondary epileptogenic foci by simultaneous extracellular recording of action potential activity and pO2 with the same microelectrode. Spike train analysis including means frequency of firing, burst analysis, and formulation of interspike interval and pO2 histograms will be conducted to quantify neuronal responses in normal cortex and in primary and secondary epileptic foci. Effects of various anticonvulsant agents including diphenylhydantoin, uridine, and taurine will be tested on neuronal action potential activity and metabolism at various stages of mirror focus development. Mathematical models will be used in conjunction with experimental analysis to investigate the temporal behavior of several metabolic processes during epileptic seizures. The models will utilize experimental data to examine in vivo feedback loops for flow and metabolic rate changes. Experimentally forced upsets will be simulated and results compared in order to back-out metabolic rate and determine transfer functions between action potential firing patterns and local oxygen tension in brain tissue. Pulse testing and correlation analysis data reduction schemes will be applied to implement on-line real-time systems analysis.